基于子结构法的升船机主传动系统的动力学建模

用动态子结构法对三峡升船机的主传动系统建立动力学模型。把整个系统分为8个一级子系统,每个一级子系统又分为4个二级子系统,建立每个二级子系统的动力学模型,利用边界条件,层层组装,最后组合成完整的动力学方程。     

Manipulating Deformable Linear Objects: Fuzzy-Based Active Vibration Damping Skill

Human can handle a deformable object and damp its vibration with recognized skill. However, for an industrial robot, handling a deformable object with acute vibration is often a difficult task. This paper addresses the problem of active damping skill for handling deformable linear objects (DLOs) by using a strategy inspired from human manipulation skills. The strategy is illustrated by several rules, which are explained by a fuzzy and a P controller. A proportional-integral-derivative (PID) controller is also employed to explain the rules as a comparison. The interpretations from controllers are translated into high level commands in a robotic language V+. A standard industrial robot with a force/torque sensor mounted on the wrist was employed to demonstrate the skill. Experimental results showed the fuzzy based damping skill is quite effective and stable even without any previous acknowledge of the deformable linear objects.Category (5)     

高层建筑屋面悬挑曲梁结构施工技术

本文通过工程实例,说明采用型钢和钢管组合支撑体系,解决高层建筑屋面悬挑曲梁结构的支模难题,保证工程质量和施工安全,并探讨施工中型钢的节点连接做法。     

辽宁省城镇居民生活用水定额

本文分析了城镇居民生活用水的特点,介绍了辽宁省城镇居民生活用水定额制定的原则、方法。通过对全省县级以上城镇居民生活用水情况的调查,制定适合辽宁省实际情况的城镇居民生活用水定额。     

Synthesis of ZSM-5 zeolite membranes without organic templates using a varying-concentration technique

Template-free nanosized ZSM-5 seeds with an average size of 15 nm were prepared from a synthesis solution with the composition 12Na2O:100SiO2:2Al2O3:2500H2O. By the use of these seeds, thin ZSM-5 zeolite membranes were prepared on the outer surface of a porous α-alumina tube with a pore size of 2 μm in a gel system by varying-concentration synthesis with organic-free template. The first composition synthesis sol-gel was the same as seeds of molar composition and the second one was 12Na2O:100SiO2:2Al2O3:5000H2O at 180 ℃ for 10 h, respectively. XRD shows that the film consists of well-crystallized ZSM-5 zeolite. SEM investigation indicats that the zeolite films on the supports are defect free and the film thickness is approximately 8 μm. The permeances for H2, N2, CH4 and CO2 are 8.94×10-7 , 3.27×10-7 , 3.9×10-7 , 3.14×10-7 and 0.874×10-7 mol·m2·s-1·Pa-1 , respectively. The ideal selectivity of membrane at room temperature for H2/CO2, H2/N2, H2/CH4 are 2.84, 2.73 and 2.29, respectively.     

刚性圆板自由落体在水面上的冲击压力

本文对一个刚性圆板自由落体在水面上的冲击过程建立了比较精确的理论模型,并建立了相应的数值格式。计算结果与已有的实验结果符合良好,通过计算进一步给出了下落质量和下落高度对冲击压力峰值的影响。     

First-principle study of ferroelectricity in PbTiO3/SrTiO3 superlattices

We performed the first-principles calculation to investigate the electronic structure and polarization behaviors in PbTiO₃/SrTiO₃ (PST) superlattices. The DOS (density of state) profiles show that there are strong hybridizations of atom Ti–O and Pb–O which play very important roles on ferroelectricity of the PbTiO₃/SrTiO₃ superlattices. Comparing to the corresponding paraelectric phase, we find the electrons of the PT (PbTiO₃) layers occupy lower energy states and electrons of the ST (SrTiO₃) layer occupy higher energy states. It is shown that the polarizations of the superlattices decrease with proportion of SrTiO₃ increasing. The constant polarization of local layer indicates that PST superlattices with small modulation lengthen can be approximately considered as a single ferroelectric material. Furthermore, according to electrostatic model, we find that directions of internal electric fields in PT and ST layers are opposite. In PST superlattices, internal electric field in PT layer leads to the loss of polarization of this layer, but the polarization of ST layer is induced by internal electric field of this layer. Compared to the value of the polarization in bulk PbTiO₃, polarization of PST is smaller.